1. Field of the Invention
The present invention relates to a microscope system, and more particularly to a microscope having a modulating optical system for modulating a luminous flux from an object as a versatile microscopic apparatus, and an image analysis method using the same.
2. Description of the Related Art
Generally, the microscope requires various adjustments in order to obtain favorable images, such as adjustment of aperture stop and field stop, modulation on a pupil plane, and other adjustments depending on the object of observation and NA of objective lens.
A typical example is a phase contrast microscope.
The phase contrast microscope is briefly explained by referring to a schematic diagram in FIG. 26.
In the following explanation, a light incident direction to a lens system is called the front side, and an exit direction is the rear side.
That is, a luminous flux emitted from a light source such as halogen lamp or a secondary light source 501 based thereon passes through a collector lens 502 disposed so that the vicinity of the front side focus plane coincide with the light source 501, and is focused on a stop 503 disposed on the rear side focus plane of the collector lens.
On the surface of the stop, a ring-shaped opening is disposed, and the luminous flux passing through the ring-shaped opening enters an object 505 through a condenser lens 504.
The luminous flux entering the object 505 passes through an objective lens 506, and the intensity and phase are modulated on a pupil plane on which a pupil modulating element 507 for modulating the pupil is disposed.
On the pupil plane, O-order component of the luminous light passing through the ring-shaped opening and passing through the object 505 is modulated by reducing the transmissivity and advancing the phase by π/2 (or delaying by π/2).
The modulated luminous flux passing through an imaging lens 508 disposed so that its front side focus plane substantially coincides with the pupil plane, and a phase image of the object 505 is formed on a rear side focus plane 509 of the imaging lens 508.
In the phase difference microscope shown in FIG. 26, in order to obtain a favorable image if the thickness or absorption of the object 505 is changed, it is required to adjust the transmissivity or phase of the pupil plane by the pupil modulating element 507. However, usually the pupil modulating element 507 is realized by a fixed film by coating, and cannot be adjusted.
Accordingly, by using liquid crystal, electrochromic or the like as the pupil modulating element 507, a microscopic apparatus capable of adjusting by controlling voltage to be applied to such element is disclosed, for example, in Jpn. Pat. Appln. KOKAI Publication No. 58-184115 and Jpn. Pat. Appln. KOKAI Publication No. 9-80313.
Going one step ahead, by combining the phase pupil modulation with the lighting system modulation such as dark field lighting, bright viewing field lighting and oblique lighting, a microscopic apparatus further advanced in versatility is disclosed in Jpn. Pat. Appln. KOKAI Publication No. 56-137324.
According to these prior arts, by using the element capable of modulating variably the lighting system and the pupil plane, it suggests possibility of composing the microscopic apparatus capable of enhancing the versatility of observation without mechanically moving a member such as turret or the like.
Actually, however, as the versatility is enhanced, it is more difficult to set the optimum value in the variable portion.
If attempted to simplify them, it is easy for those skilled in the art to consider to select by tabulating parameters of optimum variable elements depending on every method of observation or condition of the objects.
In this case, the objects may be reduced to a certain extent, but if desired to handle various objects accurately, more parameter tables are needed, and handling is more complicated.
To the contrary, if the number of tables is decreased to avoid such complicated handling, it is hard to achieve optimum handling in more objects.
Thus, in the microscopic apparatus of the prior art, it is hard to set various parameters by the variable pupil modulating element introduced for achieving the versatility optimally in various objects in a wide range, which is one of the serious problems for achieving the practical use.